Use refined butane, haveing worked in a chemical plant for 31.5yrs gas is not pure the cheaper butane has heavyes in it , doesn"t burn clean, you don"t need to purge your lighter, you need to lower the pressure in it, here"s how you do it, set lighter to lowest flame setting, put lighter in refegerator for about 5 to 8 mins, get butane can , run hot water in sink, set butane can in hot water for a couple mins, building pressure in can, take lighter out of refrigerator, you have lowered the pressure in the lighter, fill, hold for about 15 to 20 secs, wait a couple of mins and do again, lighter will be full The old cajun